Why Magnetic Components Are a Concentration Risk
Magnetic components are typically custom, low volume relative to the overall bill of materials, and positioned early in the assembly sequence. A missing transformer stops the line just as effectively as a missing microcontroller, but it is far harder to substitute because the electrical, mechanical and safety characteristics are all specific to the design. That combination of low substitutability and high impact is what makes magnetics a recognised supply chain vulnerability.
Lead Time Is Driven by the Custom Step
Standard catalogue inductors ship from stock, so their lead time is a logistics question. Custom transformers and inductors have a lead time driven by the sampling and approval cycle, tooling for bobbins or custom cores, and the batch size of the production run. Typical production lead times for standard orders run from one to two weeks, with large volume orders scheduled against material availability. Planning around the sampling and approval stage rather than only the production stage is what prevents a launch delay.
- Standard configurations generally within one to two weeks for production orders
- New custom designs need sampling and approval time before production scheduling
- Large volume orders are scheduled against material availability and negotiated in advance
- Customer priority can adjust the production schedule where materials allow
Second Sourcing Without Losing the Design
Second sourcing a magnetic component is not simply a matter of buying the same part number from another supplier. Two suppliers can both wind to the same turns ratio and inductance while producing different leakage inductance, different interwinding capacitance and different thermal behaviour, because bobbin geometry, winding pattern and varnish process differ. A genuine second source is one that can meet the same specification including the parameters that affect circuit behaviour, not just the headline values.
The practical approach is to qualify the second source against the full specification, including leakage inductance, capacitance, temperature rise and high potential, and to keep the approved construction documented so that a supplier change is a controlled engineering event rather than a purchasing decision.
MOQ and the Cost of Flexibility
Minimum order quantities for custom magnetics reflect the fact that setup, tooling and material procurement are amortised over the batch. A supplier offering an unusually low MOQ for a fully custom transformer is either absorbing the setup cost, which will return in the unit price, or planning to move the order to a subcontractor. Smaller trial quantities are often available for standard configurations, and it is worth asking which parts of a design drive the MOQ so that the design can be adjusted if flexibility matters more than the last few percent of cost.
Managing Continuity Over the Product Life
Electronic products often outlive the supplier relationships that created them. Documenting the approved construction, keeping material declarations current, and agreeing a change notification process protects continuity when a material is discontinued or a process is moved. A supplier that proactively notifies customers of material and process changes is worth more over a five year product life than one that is marginally cheaper at the start.
We support customers through sampling, production scheduling and long term continuity, and can discuss lot sizes and scheduling arrangements for products with extended production life.